The slow destruction of Venice by motor traffic has a name that residents use without needing to explain it. Moto ondoso is the wave motion generated by powered boats, and it is doing measurable structural damage to a city built on brick, timber piles, and Istrian stone that were never designed to be hit repeatedly at the waterline. The mechanism is straightforward. Wake washes against the quay walls and building foundations, scours out the mortar, and exposes the brick.